Home furnaces provide some, but not much, filtration. Their structure is often not conducive to good filtration. Typically, air is drawn down cold air returns into the furnace. The cold air returns are located in various rooms throughout the house. At the end of an inlet duct, to which the cold air returns are joined, there is a filter ahead of a blower. The blower on a furnace is usually a large and sometimes multiple horsepower motor that can easily distribute air through the house. The filter on a furnace typically serves only one function, and that is to remove large particulates.
Small particulates and odors are more effectively filtered out of the air in a multistage process. Odors are not often dealt with in an ordinary furnace filter. The treatment of air, such as distributing chemicals, medications, aromas, or other deodorizers is not possible through an ordinary furnace filter. Some filters which claim to be able to filter small particles or odors from the air are unsuitable because most standard furnaces do not have sufficiently powerful blower motors to move air through the tight weave patterns of these filters. As such, an improved furnace filtration system is needed.